Tank trucks for collecting and transporting flowable refuse materials, such as storm drain sewage, septic tank sewage, certain chemical waste, leaves and the like, are typically equipped with a collection tank, a vacuum pump, and an at least partially flexible suction hose having one end connected to the tank and an opposite end (i.e., distal end) including a refuse pick-up nozzle. The suction hose may be supported by an adjustable boom on the truck so that at a site of refuse pick-up, the nozzle may be manipulated and positioned relative to the parked truck. For efficient and safe operations, it is desired to provide the ability to adjust the length of the suction hose between the tank of the truck and the pick-up nozzle.